The invention relates generally to the construction of low-temperature or cryogenic storage tanks used, for example, to store large quantities (for example, ½ million barrels or more) of volatile materials such as natural gas. In particular, the invention relates to ways to efficiently insulate parts of such tanks.
Conventionally, low-temperature or cryogenic tanks have an outer shell around an inner tank. Process piping extends between the outer shell and the inner tank, and a thermal distance piece (TDP) is used to insulate that process piping. The TDP creates as an enclosed internal space or void that can be insulated using a fiberglass blanket, field-cut fiberglass disks, perlite fill, or other granular insulating material. Conventionally, perlite fill has been pneumatically blown into the void within the TDP through a face plate. This process has been viewed as satisfactory.
The applicants have found a way to fill the void within a TDP more efficiently, with less waste and with less environmental impact.